I definitely had this issue with the first generation Raspberry Pi. It wasn't just a corrupted filesystem. The SD card was completely ruined. When I started over, I followed instructions to make the file system readonly, turn off the tmpfs, turn off atime, etc. And never had another issue. Eventually I replaced the Pi with a newer one and haven't had any problems even though the file system is read/write. I think this issue may have affected the earlier models more, or maybe SD cards are better now.